Stable and Biocompatible Mushroom β-Glucan Modified Gold Nanorods for Cancer Photothermal Therapy

Naturally occurring β-glucans have been widely regarded as a natural source for functional foods and pharmaceuticals due to their immunomodulatory property and antitumor activity. However, physicochemically stable and biocompatible β-glucans are rarely explored as a carrier for nanomaterials to overcome the problems of aggregation and nanotoxicity. Here, we developed highly stable and biocompatible mushroom β-glucan coated gold nanorods (AuNR-Glu) for cancer photothermal therapy by integrating Pleurotus tuber-regium sclerotial β-glucan (Glu) and plasmonic gold nanorods (AuNRs) possessing photothermal property in the second near-infrared (NIR-II) window. AuNR-Glu showed high colloidal stability in various biological media, even in simulated gastric fluid. Moreover, AuNR-Glu had low cytotoxicity and high photothermal stability, which are excellent characteristics for photothermal agents for cancer therapy. In vitro experiments showed that AuNR-Glu nanohybrid was effective against MCF-7 (only 4.5 ± 0.9% viability) at a low dose of 20 μg/mL under NIR-II at a safe laser power density (0.75 W/cm²). Natural mushroom β-glucans are potential functional polymers that can be used to fabricate nanohybrids for biomedical applications.